The invention generally pertains to variable tension lacing systems for footwear. More particularly, the tension systems permit adjustment of selected zones of the footwear lacing system, to provide an improved fit and to prevent discomfort during use.
There are numerous systems that currently exist for tightening footwear about the foot of a wearer. The most common includes threading a lace in a zig-zag pattern through two parallel rows of eyelets that are placed on opposite sides of a tongue area of a shoe or boot. The shoe is tightened by pulling on opposite ends of the threaded lace to pull the two rows of eyelets together so that the closure edges of the cuffs are urged toward the middle of the foot, and then tying the lace ends in a knot to maintain the desired tension. There are a number of known problems with such traditional systems, including that the tightening force is not adequately distributed along the length of the threaded zone due to friction between the laces and eyelets. Thus, some portions of the lace may be slack while other portions are taut which results in certain portions of the shoe being tighter around certain sections of the foot, particularly the ankle portions which are closer to the lace ends. This can cause discomfort and may adversely affect performance when the wearer is involved in a sports activity.
Conventional lacing systems are also typically difficult to untighten and/or difficult to readjust in order to redistribute tension because the wearer must loosen and adjust the lace from each of many eyelets. Simply untying the knot does not release the lace because friction between the lace and eyelets and between overlapping laces often maintains the toe portion and sometimes even much of the other areas above the foot in tension even after the knot is released. Consequently, a wearer often must loosen the lace from each individual eyelet, which can be tedious if the number of eyelets is high, for example, such as in an ice skate boot, a snowboard boot, or other high-performance sports footwear.
Certain sports footwear, such as ski boots use tightening mechanisms that include buckles that clamp together to tighten the boot about the foot. Such systems typically use three or four buckles positioned about the tongue area of the boot, and can be quickly clamped to tighten and unclamped to loosen the boot about the foot. However, such systems isolate the closure forces about the immediate area of the buckle which can be undesirable in many circumstances, such as when the wearer is engaged in a sport that requires an evenly distributed force line along the length of the foot. In addition, buckles tend to be uncomfortable if used on some types of footwear, such as soft boots, and thus are primarily used only on hard-shell type footwear such as ski boots.
Other footwear lacing systems have been developed that include a lace or cable attached to a tightening mechanism. In one such system, the lace is threaded through a series of opposing guide members positioned along the top of the foot and ankle portions of the footwear. The tightening mechanism operates to wind up the lace to tighten the shoe about the foot, and to wind out the lace to release tension. The lace and guide members have low friction surfaces to facilitate sliding of the lace through the guide members to promote the even distribution of tension across the footwear. However such systems cannot be used to isolate any specific region where a user may wish to increase or decrease tension. Further, as a wearer performs certain maneuvers, some sections of the system become constricted due to stress forces which causes discomfort. For example, snowboard riders wearing boots that include such a system have complained that the lace, which is typically a cable, tightens and causes discomfort across a lower portion of the tongue during flexion. A need thus exists for a tension lacing system that can be adjusted by a user to avoid discomfort that may occur when a shift in tension forces occurs during use.